title: Quantum signatures of breathers in a finite Heisenberg spin chain.
abstract: A map of a quantum Heisenberg spin chain into an extended Bose-Hubbard-like Hamiltonian is set up. Within this framework, the spectrum of the corresponding Bose-Hubbard chain, on a periodic one-dimensional lattice containing two, four, and six bosons shows interesting detailed band structures. These fine structures are studied using numerical diagonalization, and nondegenerate and degenerate perturbation theory. We also focus our attention on the effect of the anisotropy and Heisenberg exchange energy on the detailed band structures. The signature of the quantum breather is also set up by the square of the amplitudes of the corresponding eigenvectors in real space.
authors.affiliation: Nonlinear Physics and Complex Systems Group, Département de Physique, Ecole Normale Supérieure, Université de Yaoundé I, PO Box 47, Yaoundé, Cameroon.
authors.forename: Z I
authors.initials: ZI
authors.lastname: Djoufack
authors.forename: A
authors.initials: A
authors.lastname: Kenfack-Jiotsa
authors.forename: J P
authors.initials: JP
authors.lastname: Nguenang
authors.forename: S
authors.initials: S
authors.lastname: Domngang